Electro-optic systems comprised of optical fibers and electro-optic components are used in a wide variety of commercial applications, such as in telecommunication of data and the like.
The optical fibers which are commonly employed have a relatively small diameter core comprised of an optically transparent material and a cladding layer of a polymeric material around the outer surface of the core which acts to inhibit the dissipation of light from the core. Since optical fibers are relatively weak, they are subject to breakage when strain is applied to them. In addition, if strain is applied to an optical fiber within an electro-optic system, the terminal end of the optical fiber can be forced out of alignment with an electro-optic component, causing the electro-optic system to become inoperative. The optical fibers conventionally are protected by being encased in a fiber optic cable. The most commonly employed type of fiber optic cable has an optical fiber in the center of the cable, a plurality of reinforcement strands positioned circumferentially about the optical fiber and aligned with the length of the optical fiber so as to be capable of relieving strain on the optical fiber, and an outer jacket disposed over and about the reinforcement strands.
The electro-optic components include many different types of devices, such as light emitters, light detectors, signal repeaters and the like. Many of the electro-optic components are highly sensitive to environmental contaminants and are highly susceptible to physical damage. To prevent damage to the components the components are sealed in protective component housings. The component housings are made in various shaped configurations to accommodate the different types of devices but they all include an opening for passage of an optical fiber through to the interior of the component housing.
When connecting a fiber optic cable to an electro-optic component, a terminal end of the optical fiber must be precisely aligned with the electro-optic component packaged in a component housing and secured in position. The component housing is then preferably hermetically sealed and the remaining portions of the fiber optic cable, that is, the reinforcement strands and the jacket, are trimmed and secured to the component housing with a mechanical fiber optic cable coupler or a length of heat-shrink tubing.
The terminations of the fiber optic cables to the component housings present serious production and performance problems. In order for the fiber optic cable to protect the optical fiber from strain, the ends of the reinforcement strands must be locked in position so as to absorb any strain placed on the fiber optic cable. Certain of the suggestions heretofore made for terminations required a relatively complex series of steps and a skilled operator to make an even marginally satisfactory termination. Other suggestions required special fittings similar to those used to couple lengths of fiber optic cable together, which couplings resulted in the connection being excessively large. The most serious problem encountered with the suggested methods was that they did not provide adequate strain relief so as to prevent breakage and misalignment of the optical fibers with the components.
It would be highly desirable if a method could be provided for making a termination of a fiber optic cable with a component housing, which termination would be simple to make, compact and would provide sufficient strain relief so as to protect the optical fiber from breakage and misalignment.